Project Summary The purpose of this Mentored Research Scientist Career Development Award (K01) application is to develop Dr. S. Wilson Beckham?s career as an independent investigator in implementation science to optimize evidence-based HIV interventions in low-income countries, particularly among sexual and gender minorities. This K01 will provide the necessary support to achieve the following goals: 1) to become an expert in implementation science theories and methods in public health; 2) to gain training in the theory and application of stated-preferences methods, particularly discrete-choice experiments (DCE); 3) to conduct preference heterogeneity analyses of stated-preference data using latent class finite-mixtures models; 4) to become an expert in pre-exposure prophylaxis (PrEP) implementation research. To support these goals, Dr. Beckham has a mentoring team of his primary mentor, Dr. Deanna Kerrigan, a specialist in implementation of community- based HIV interventions for high-risk women; three co-mentors, Dr. John FP Bridges, an expert in stated- preferences methods; Dr. Chris Beyrer, a leading HIV researcher with expertise in PrEP implementation for high-risk populations; and Dr. Noya Galai, a biostatistician who applies her skills to the development and application of methods to public health, and a collaborater, Dr. Jessie Mbwambo, a leading researcher in sub- Saharan Africa (SSA), specializing in implementing HIV interventions for high-risk populations collaborators at Emory University, Drs. Patrick Sullivan and Travis Sanchez. Given the high burden of HIV among men who have sex with men (MSM), integrating PrEP into HIV services is an urgent priority and requires implementation science research to identify optimal patient-focused strategies and drug formulations (e.g. tablet, injectable, cervical ring) that are acceptable to the intended populations and reaffirm their dignity, rights, and choice. The goal of this study is to measure MSM?s preferences for injectable PrEP and explore healthcare provider-level challenges, to inform future optimal implementation of PrEP into community-based interventions. To achieve these goals, this study has the following research aims: 1) Quantify MSM?s stated preferences for PrEP by designing and conducting a discrete choice experiment (DCE) using key attributes of long-acting injectable PrEP among n=2,241 MSM in the US. This aim will embed and analyze a DCE in the American Men?s Internet Survey (AMIS). 2) Identify preference heterogeneity across the different attributes of PrEP using a latent class finite-mixture model to account for differences between groups of respondents (?latent classes?). 3) Identify barriers and facilitators to healthcare providers? willingness to prescribe LAI-PrEP to MSM and develop a provider readiness tool, based on the adaptable Tailored Implementation for Chronic Diseases. This aim will employ semi-structured interviews among providers of HIV-related healthcare (n=28), and the determinants of practice checklist to guide the development and refinement of the tool. This training and research plan will produce preliminary data to inform an R01 application to conduct implementation research on integrating preferred formulations of PrEP into combination prevention interventions for key populations.